Kuala Lumpur. Overcrowded cities in developing nations could tackle unmanaged urban sprawl more effectively by creating 30-year plans based on acquiring cheap land adjacent to their suburbs and developing those new areas in a sustainable way, experts said on Monday (12/02).

Some urban planners and researchers are trying out an idea proposed by the New York University Marron Institute of Urban Management for cities to buy land and then partner with the private sector to build affordable housing, transport links, good sanitation and recreational areas there, said Anjali Mahendra of the United States-based World Resources Institute (WRI).

"Cities need to project their needs of urban growth for the next 30 years, figure out the locations where they can accommodate that growth, and go and acquire that land," Mahendra, who is investigating the approach, told the Thomson Reuters Foundation on the sidelines of the World Urban Forum, the world's biggest conference on cities.

Some 4 billion of the world's 7.4 billion people live in urban areas, the World Bank says. By 2045 it expects that to rise to 6 billion.

Asia Pacific is one region urbanizing at an unprecedented pace. More than half its population lives in urban areas, and that will climb to two-thirds by 2050, the United Nations says.

But economic inequality is high in many Asia-Pacific cities, which are struggling with poor infrastructure, a shortage of affordable housing, patchy access to essential services, and the effects of climate change.

"There are dense, unserviced settlements within cities that have very poor quality of life," said Mahendra, who leads research at WRI's Ross Center for Sustainable Cities.

About 1.5 billion people in Asia lack basic sanitation services, for instance, while 250 million people live in slums, the Asian Development Bank (ADB) and the World Bank say.

For cities to be able to buy land around their boundaries, which tends to be cheaper as it is still undeveloped, they need greater powers from central governments to raise capital and invest in major infrastructure projects, while negotiating with those who use that land such as farmers, researchers said.

Transparency and land ownership laws would also need to be bolstered in many countries to stop corruption and speculation by private developers, Mahendra said.

Time limits should be imposed on real estate developers that buy land in and around cities but do nothing with it for decades, she added.

Colombian cities like Valledupar and Montería have begun using the approach to manage urban expansion, with support from New York University. But in some other places like India it has not worked well, experts noted.

When purchasing the land, cities must have regulations in place to ensure the right kind of clean, green development through partnerships with the private sector, Mahendra said.

Development finance organisations and institutional investors have money ready to put into high-quality urban projects, the president of the 100 Resilient Cities network told the Thomson Reuters Foundation last week.

In 2017, the ADB spent $4.5 billion on climate change projects, which it hopes will rise to $6 billion a year by 2020.

Development in many Asian cities experiencing rapid urbanization is often unstructured and unsustainable, said Manoj Sharma, an urban development specialist at the ADB in Manila.

A 30-year plan to address urban expansion in a more controlled and environmentally friendly way would be a step forward, he added.